The fate of the world\u2019s oceans may rest inside a stainless steel tank not quite the size of a small beer keg. Inside, genetically modified bacteria turn corn syrup into a churning mass of polymers that can be used to produce a wide variety of common plastics.<\/p>\n
\u201cIt\u2019s a bit like making yogurt,\u201d said Oliver Peoples, chief scientific officer of Metabolix, Inc.<\/p>\n
The Cambridge, Massachusetts\u2013based company where bioplastics take shape in laboratory-scale fermentation chambers is one of a growing number of businesses and institutions working to develop cost-competitive, more environmentally friendly replacements for conventional plastics, which are made from fossil fuels, fail to decompose and are turning our oceans into seas of floating plastic.<\/p>\n
\u201cWe\u2019ve seen this huge increase in production in plastic that results in an increase in the waste stream as well,\u201d said Jenna Jambeck, an environmental engineering faculty member at the University of Georgia. \u201cUnlike material that biodegrades, plastic has all of these issues. It easily travels into waterways, it physically fragments into smaller pieces which are extremely hard or impossible to collect, and [it tends to] absorb chemical contaminants that are already in the environment.\u201d<\/p>\n
Some 5.3 million to 14 million tons of plastic, or up to 4 percent of the roughly 330 million tons of plastic produced each year, entered the ocean as trash in 2010. The figure is expected to increase tenfold in the next decade as more plastic is produced and subsequently evades waste management and recycling efforts, according to a study Jambeck and colleagues published earlier this year in the journal Science.<\/p>\n
What effect all this plastic has on living things, including humans, remains unclear. A number of recent studies show that chemicals in small bits of plastic, and even the plastic bits themselves, can accumulate in birds, fish and other marine life. Laboratory testing has shown the chemicals that comprise them can cause adverse health effects, including liver damage and endocrine disruption through altered gene expression.<\/p>\n
Whether similar effects occur outside the laboratory or whether they extend up the food chain to people who eat marine organisms remains unknown, yet both seem entirely plausible.<\/p>\n
And that\u2019s not all. Plastics are notorious in the greenhouse gas department as well. Roughly 8 percent of the petroleum used worldwide each year goes to make plastic directly or to power the plastic manufacturing processes, according to a recent report by the Worldwatch Institute.<\/p>\n
Why not just reduce our use? For one thing, plastics are incredibly versatile, meeting a spectrum of needs for flexibility, cost and other parameters that substitute materials would be hard put to match. Not only that, but substitute materials present their own adverse environmental, social and health impacts.<\/p>\n
\u201cEven though people feel like they would like to use less plastic rather than more, the fact of the matter is that plastics are modern materials that make cars lighter, purify water and add tremendous benefit to health and security applications,\u201d said Marc Hillmyer, director of the Center for Sustainable Polymers at the University of Minnesota in Minneapolis.<\/p>\n
In other words, there are solid reasons for pursuing more sustainable alternatives to conventional plastics \u2014 namely, plant-based plastics. Such so-called bioplastics are able to degrade, dramatically reducing the risk that they\u2019ll end up polluting land or sea.<\/p>\n
They also lower our dependence on fossil fuels, reducing plastic\u2019s carbon footprint. Greenhouse gas emissions associated with bioplastics are 26 percent lower than those associated with conventional plastic, according to a recent life-cycle analysis of corn-based and petroleum-based plastic by researchers at Michigan State University.<\/p>\n
Emerging alternatives<\/p>\n
Finding non-petroleum-based, decomposable alternatives to today\u2019s plastics, however, isn\u2019t easy. Plastic made from corn, sugar cane or other plant-based material isn\u2019t necessarily degradable, and getting degradation to occur when you want it to can be difficult.<\/p>\n
\u201cYou don\u2019t want your plastic bag to degrade while you are using it,\u201d Hillmyer said. \u201cOn the other hand, you want it to degrade rapidly when put into another environment.\u201d<\/p>\n
While chemists have had difficulty reformulating petroleum-based plastics so that they can degrade, a number of bio-based, degradeable alternatives are emerging.<\/p>\n
Despite these and other recent successes, bioplastics remain a tiny fraction of the industry as a whole. Natureworks, a company based in Minnetonka, Minnesota, is one of the world\u2019s leading manufactures of bioplastics. The company makes polylactic acid, or PLA, a biodegradable plastic it sources from cornstarch and makes into a wide range of consumer products \u2014 including single-use flatware, cups and packaging \u2014 that decompose at the end of their useful life.<\/p>\n
The company\u2019s initial production facility in Blair, Nebraska, came online in 2002 and can produce 150,000 tons of PLA per year. The company recently announced plans to open a second plant in Southeast Asia that would use sugar cane as its feedstock.<\/p>\n
Another leading manufacturer of bioplastic is the Coca-Cola Company, which in 2009 launched PlantBottle, a drink bottle made from polyethylene terephthalate \u2014 PET \u2014 that contains up to 30 percent biobased material.<\/p>\n
The bottles are not degradable but, unlike most biobased plastics, can be recycled along with conventional PET, a commonly recycled plastic. Since 2009 the company has produced 35 billion of its original PlantBottles. In June, the company unveiled a new version that is 100 percent biobased.<\/p>\n
Despite these and other recent successes, bioplastics remain a tiny fraction of the industry as a whole. The materials are well suited for single use products such as spoons and bottles where consumers are willing to pay a premium for more sustainable products.<\/p>\n
High durability, less-visible applications \u2014 for example, water pipes made of PVC that are commonly used in residential and commercial plumbing \u2014 are still made entirely of conventional plastic. In total, less than 0.5 percent of all plastic comes from non-petroleum sources, according to the Society of the Plastics Industry, an industry trade group based in Washington, D.C.<\/p>\n
Government regulation, however, is leading to the increased use of bioplastics. In 2014 Illinois banned microbeads, tiny plastic abrasives commonly used in facial scrubs, shampoo and toothpaste, due to concerns about environmental degradation in the Great Lakes. At less than 1 millimeter in diameter, microbeads are too small to be filtered by sewage treatment systems and have been found in both freshwater and marine environments.<\/p>\n
With a federal ban on microbeads expected, Metabolix partnered with Honeywell in March to produce a biodegradable alternative to microbeads. The microbeads the two companies are developing are made from polyhydroxyalkanoates, or PHA, a bio-based plastic that is more expensive but also more versatile than PLA.<\/p>\n
The microbeads the two companies are developing are made by fermenting cornstarch, although they also could be made from non-food crops such as switchgrass. PHA microbeads will degrade into carbon dioxide and water in a matter of months at the same rate as cellulose or paper, Peoples said.<\/p>\n
Around the downsides<\/p>\n
As we increase our reliance on plastics sourced from crops such as corn or sugar cane, we inadvertently could introduce new environmental concerns.<\/p>\n
A recent study in the journal Cleaner Production noted bioplastics grown from agricultural feedstocks use significant amounts of water, pesticides and fertilizers that can cause air and water pollution and compete for land with crops grown for food.<\/p>\n
One possible way to get around the downsides of plant-based plastics while still reducing dependence on petroleum is to use CO2 as a feedstock instead.<\/p>\n
Novomer, a company spun out from research at Cornell University in Ithaca, New York, is turning waste CO2 from ethanol production plants into plastic. The company makes polyols \u2014 polymers used to make flexible foam found in mattresses, seat cushions and insulation, as well as a range of specialty coatings and sealants.<\/p>\n
\u201cIf your mattress was made with our material, it would be roughly 22 percent by weight carbon dioxide,\u201d said Peter Shepard, Novomer\u2019s executive vice president of polymers. \u201cIt takes a greenhouse gas that is a waste material and turns it into a valuable product.\u201d<\/p>\n
Typically CO2 is too inert to react with other compounds, making its use in plastics or other applications difficult. Geoffrey Coates, a chemistry professor at Cornell University in Ithaca and a co-founder of Novomer, developed a catalyst that increased the reactivity of CO2 while simultaneously slowing down the reactivity of another key polyol ingredient \u2014 making it easier to incorporate CO2 into the resulting polymer.<\/p>\n
\u201cIt\u2019s like if you have kids and you give them pizza and broccoli and you tell them every time you take a bite of pizza you have to take a bite of broccoli,\u201d said Coates, also a member of the Center of Sustainable Polymers.<\/p>\n
The biggest challenge for bioplastics is that they are competing against conventional plastics, incredibly inexpensive materials that have been honed for the past 60 years, Scheer said. The polyols made by Novomer are degradable but lose their degradability when combined with petroleum-based chemicals to make foam.<\/p>\n
Although the company is currently focused on making foams and sealants, Shepard said Novomer\u2019s CO2-based polymers could be used to make degradable plastics with a CO2 content as high as 50 percent.<\/p>\n
Biggest challenge<\/p>\n
Despite strong growth in recent years, some say bioplastics haven\u2019t lived up to their potential.<\/p>\n
\u201cThe bioplastics industry has not been able to create polymers that are attractive enough in terms of pricing and in terms of properties that will make the world willing to change,\u201d said Frederick Scheer, former CEO of Cereplast, a once-leading bioplastics company that declared bankruptcy in 2014.<\/p>\n
The biggest challenge for bioplastics is that they are competing against conventional plastics, incredibly inexpensive materials that have been honed for the past 60 years, Scheer said.<\/p>\n
\u201cPeople are somewhat conscious of the environmental impact of oil-based materials that will not biodegrade, but they are not willing to spend the extra dollars to push [new] types of materials,\u201d he said.<\/p>\n
Competition with petroleum-based plastic has intensified over the past year as the price of oil has dropped in half.<\/p>\n
\u201cIn order to be competitive with traditional oil-based material, we needed the price of oil to be somewhere around $130, $140 a barrel,\u201d Scheer said. \u201cClearly, at $50 a barrel we are far away from being able to compete.\u201d<\/p>\n
Scheer said the capacity to make all of the world\u2019s plastic from non-petroleum sources exists, but to do so would require significant government support.<\/p>\n
\u201cIt will have to be driven by regulation that will force the cost of plastic and cost of oil to be substantially higher than it is right now,\u201d he said.<\/p>\n
Polyethylene competitor?<\/p>\n
If sustainable plastics that reduce our dependence on fossil fuels and degrade at the end of their useful life are to go mainstream, they will have to be able to sub in not only for microbeads, foam and other specialty applications but also for thermoplastics \u2014 low-cost, shapeable polymers that comprise more than 80 percent of the hundreds of millions of tons of plastic produced each year.<\/p>\n
Coates is working on a new biopolymer with properties comparable to or perhaps better than polyethylene, the most widely produced thermoplastic used to make everything from trash bags to water bottles to plastic toys.<\/p>\n
Even a thin layer of polyethylene is incredibly strong, making, for example, mailing envelopes that are nearly impossible to open without scissors or milk jugs that don\u2019t break when dropped on the floor. \u201cMost of that is because it\u2019s a semicrystalline material,\u201d Coates said. \u201cThe [polymer] chains pack next to each other in a very tight and specific fashion that overall gives pretty impressive properties.\u201d<\/p>\n
In a 2014 study published in the Journal of the American Chemical Society, Coates and colleagues at Cornell described a new material with a semicrystalline structure that is made from a sugar feedstock and has properties similar to polyethylene, yet is better able to decompose at the end of its useful life.<\/p>\n
\u201cIt doesn\u2019t happen overnight, but I think there are certain positive [indications that it] could be a real competitor for a plastic like polyethylene,\u201d Hillmyer said.<\/p>\n
The new material, known as poly(polypropylene succinate), hasn\u2019t been tested to see how quickly it would decompose in a landfill or marine environment. But based on its composition, Coates said, it should begin to degrade in water after several months, a time period that would exceed the useful life of most single-use products. Poly(polypropylene succinate) breaks down into propylene glycol and succinic acid, nontoxic materials that are further reduced to CO2 and water when ingested by microbes.<\/p>\n
\u201cIf you had to eat polymer degradation products, these would be the ones you want,\u201d Coates said.<\/p>\n
It\u2019s unlikely that poly(polypropylene succinate) will cost less on a pound-for-pound basis than conventional polyethylene, but its unique crystalline structure suggests it could perform better than its petroleum counterpart. If so, bioplastics manufacturers\u00a0 someday may be able to compete with today\u2019s plastics industry by making things such as milk jugs with significantly less material than petroleum-based plastics.<\/p>\n
Uphill battle<\/p>\n
Short of sweeping government regulations that place a price on carbon or require all plastics to biodegrade, bioplastics will have to find ways to outcompete conventional plastics if they are to fill more than niche applications.<\/p>\n
It\u2019s an uphill battle \u2014 but one that another once-niche product, the solar panel, is increasingly winning.<\/p>\n
In 2007, solar power made up less than 0.1 percent of U.S. electricity generation. Thanks to ingenuity and innovation, the price of photovoltaic modules has dropped from $4 per watt to $0.50 per watt, making solar the fastest growing source of electricity in the country.<\/p>\n
Might those working on bioplastics see a similar sea change? Ultimately, a lot likely will ride not only on how well their products break down, but on how much they can break down conventional plastic\u2019s competitive edge.<\/p>\n","protected":false},"excerpt":{"rendered":"
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